/* --------------------------------------------------------------------- 
** Figure 17.9:   Calculating wind speed.
** Figure 17.10:  Printing the wind speed table.
** --------------------------------------------------------------------- 
*/
#include "tools.h"    

#define N   5   
typedef double velocity[3];

double sqr( double x ){ return x * x; }
double speed( velocity v ){ return sqrt( sqr(v[0]) + sqr(v[1]) + sqr(v[2]) ); }
void   print_table( string names[], bool mask[], velocity w[] );

void main( void )                                                                                                               
{   
    int city;  
    double windspeed; 

    velocity wind [N];
    bool mask[N] = { 0 };                 /* Initialize all masks to false. */                
    string names[N+1] = { "Tweed",     "Bradley",    "Sikorsky",
                          "Hamden MS", "Bridgeport", "--finish--" };                  

    banner();                                              
    printf( "\n Wind Speed \n" );
  
    for (;;) {
        city = menu_i( " Station reporting data:", N + 1, names );
        if (city == N) break;           /* User selected "quit" */

        printf( " Enter wind components for %s: ", names[city] );
        scanf( "%lg%lg%lg", &wind[city][0], &wind[city][1], &wind[city][2] ); 
        mask[city] = true;                           
        windspeed = speed( wind[city] );
        printf( "\t Wind speed is %g.\n", windspeed); 
    }                                                      
    print_table( names, mask, wind );        
    bye();                                   
}

/* ---------------------------------------------------------------------- */
void 
print_table( string names[], bool mask[], velocity w[] )
{   
    int k;
    puts( "\n Wind Speeds at Reporting Weather Stations" );
    for (k = 0; k < N; ++k) {
        if (mask[k]) 
            printf( " %-15s (%7.2f %7.2f %7.2f )  speed: %6.2f\n", 
                    names[k], w[k][0], w[k][1], w[k][2], speed(w[k]) );
    }
}